The present invention relates to a method of producing aerated soap from aerated molten soap. More particularly, it relates to a method of producing aerated soap while preventing separation of the molten soap into gas and liquid.
Applicant of the present invention has previously proposed in JP-A-10-195494 a method of producing aerated soap which comprises solidifying molten soap containing a large number of bubbles in a cavity of a mold, wherein the step of solidification is carried out in a hermetically closed cavity.
According to this production method, outside air not being allowed to enter the cavity, the solidified soap hardly suffers from void or depression development. However, when the operation of aerated soap production is suspended in case of some trouble, molten soap stagnates in the feed piping or the storage tank. Meanwhile the bubbles gather to gain in diameter, resulting in separation into gas and liquid. If the operation is resumed in this state, the molten soap would be injected into the cavity with gas separated from liquid. It follows that the resulting soap has bubbles dispersed non-uniformly and reduced latherability on use. Where a stirring wing (stirring blade) is used, which is the most common means of agitation, it would be difficult to break the gathered bubbles to restore a gas/liquid dispersed system at a low shearing force, or air would be entrained at too high a shearing force, causing a change in specific gravity of the molten soap. Further, variation in the state of bubbles (especially the amount of bubbles) can result in variation in the weight of solidified soap.
Accordingly, an object of the present invention is to provide a method of producing aerated soap while preventing separation of molten soap having a great number of bubbles dispersed therein into gas and liquid.
Another object of the present invention is to provide a method of producing aerated soap which secures uniform dispersion of bubbles and minimizes weight variation among solidified soap products.
The present invention accomplishes the above objects by providing a method of producing aerated soap which comprises solidifying molten soap having a large number of bubbles dispersed therein in a molding unit, wherein
a circulating duct is connected to a storage tank of the molten soap to form a loop passing through the storage tank,
the circulating duct or the storage tank has connected thereto a feeding section for feeding the molten soap, and
the molten soap is fed to the molding unit through the feeding section while being circulated through the circulating duct.
The present invention also provides an apparatus for producing aerated soap which is used to carry out the above-described method of producing aerated soap, which comprises a storage tank for molten soap, a circulating duct connected to the storage tank and forming a loop passing through the storage tank, a molten soap feeding section which is connected to the circulating duct or the storage tank, and a molding unit where the molten soap fed from the feeding section is molded and solidified into a prescribed shape.